JP2938997B2 - Lithographic printing plate developer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer used for a lithographic printing plate prepared by a silver complex salt diffusion transfer method.

[0002]

2. Description of the Related Art An offset printing plate using a silver image obtained by a silver complex salt diffusion transfer method (DTR) has already been disclosed in Japanese Patent Publication No. 46-43232 or Japanese Patent Publication No. 48-3.
No. 0562, and a positive-type printing original plate is disclosed in JP-A-49-55402.
For a negative-type printing original plate, see Japanese Unexamined Patent Publication No.
No. 106902, JP-A-52-112402 and the like.

[0003] These direct printing plates are composed of a support, an undercoat layer for preventing halation thereon, a silver halide emulsion layer, and a physical development nucleus layer. When the photosensitive material is imagewise exposed and then processed with a developer containing a developing agent and a silver halide solvent, a latent image is formed.The silver halide is blackened in the emulsion layer. The silver halide in which is not formed is dissolved by the action of the silver halide complexing agent and diffuses to the surface of the light-sensitive material. A printing plate is obtained by a process in which this silver complex salt is deposited as a silver image on the physical development nuclei of the surface layer by the reducing action of the developing agent.
In order to enhance the ink receptivity of the silver image, after development, if necessary, a sensitization treatment is performed, and the ink image is transferred to a printed material on an offset printing machine. This direct printing plate has advantages such as good operability and low price, but on the other hand, diffusion transfer is not completed within the processing time due to the nature of forming a silver image for printing by photographic development processing. In addition, excessive silver ions remain, which is one of the causes of the deterioration of storage stability or printing durability.

[0004] Various methods are used to remedy these drawbacks. One is the use of oxidants. JP-A-55-98753 describes the combined use of a sulfur-containing organic compound and an oxidizing agent.
No. 52 and No. 61-223740 describe a method of improving printing durability using iodine ions and an oxidizing agent. The removal of excess silver ions by using a chelate resin was also effective in increasing printing durability. However,
A disadvantage of these methods was that they often tended to reduce the ink acceptance of the silver image. In addition, Japanese Unexamined Patent Publication No.
Nos. 7- 211148 and 58-156936,
A method of using a thione compound as a physical development accelerator is described. These methods are superior to the above methods in terms of ink adhesion and printing durability, but cause photographic disadvantageous changes in properties, such as softening, resulting in a reduction in printing durability. there were.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a processing solution for obtaining a silver image having high printing durability and high ink acceptability in the development of a direct lithographic printing plate utilizing a silver complex salt diffusion transfer method. It is to provide.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide at least one kind of physical development accelerator represented by Chemical formula 2 and an organic development inhibitor having no mercapto group and thione group in the above-mentioned developing solution. (Hereafter, organic development control without mercapto group
(Referred to as an antimicrobial agent) .

[0007]

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In the formula, R represents an alkyl group, an aryl group , an aralkyl group, or a hydroxyalkyl group, and X represents Se,
It is a hetero atom of S, O, or N, or a methylene group or an alkyl-substituted methylene group, and Z represents a group of remaining atoms necessary to form a 5- or 6-membered ring.

Representative specific examples of the compound of formula 2 used in the present invention are shown below.

[0010]

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[0011]

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[0012]

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[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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These compounds are described, for example, in Journal of Organic Chemistry 36, 637 (1
971) [J. Org. Chem. 36 637 (1
971)], Synthesis, p. 807 (1984) [S
synthesis807 (1971)], synthesis
96 (1983) [Synthesis 96 (1
971)], Chemical Pharmaceutical Britain, Vol. 31, p. 1733 (1983) [Chem Ph.
arm • Bull 31 1733 (1983)], Organic Syntheses Vol. 7, p. 195 [Organi
c. Synthesis, Coll. vol. 7 1
95 (1990)] and JP-A-62-246558. The amount of the compound of the formula (2) of the present invention added to the developer is 0.01 to 1% by weight.
It is in the range of 0.0% by weight, particularly preferably in the range of 0.01 to 4.0% by weight, and a single compound or a combination of two or more compounds can be used.

The organic development inhibitor having no mercapto group used in combination with the processing solution of the present invention may be used alone or in combination of two or more. Any compound may be used as long as it has no mercapto group and no thione group . Benzotriazole or benzimidazole and its derivatives were particularly effective.
The organic development inhibitor used in the present invention is a mercapto group
And a compound having no thione group . Representative specific examples are shown below.

[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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The amount of the organic development inhibitor added to the processing solution is preferably 0.01 to 2.0% by weight in terms of weight ratio, and the ratio to the chemical formula 2 is 0.01 to 1.0% by weight. preferable.

It is known to use a water-soluble polymer such as carboxymethylcellulose (CMC) or hydroxyethylcellulose (HEC) as a thickener in a diffusion transfer developer for lithographic printing plates (see, for example, JP-A-48-7660).
3, 6 and 56) may be added to the processing solution of the present invention, but these high molecular compounds do not have the effect of improving the printing durability.

The developing solution of the present invention contains an alkaline substance,
For example, sodium hydroxide, potassium hydroxide, sodium tertiary phosphate and the like and sulfites (potassium sulfite, sodium sulfite, etc.) as preservatives are essential, but other compounds such as sulfates (sodium sulfate, ammonium sulfate, etc.) ), Antifoggants such as potassium bromide, silver halide solvents such as thiosulfate, thiocyanate,
Thickening agents such as thioether, cyclic imide, thiosalicylic acid, alkanolamine, etc., for example, hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CM
C) and the like, and developing agents such as hydroquinone, 1-phenyl-3-pyrazolidone, and methanol, and development modifiers such as polyoxyalkylene compounds and onium compounds. Further, one or more surfactants such as propylene glycol alginate, aminopolycarboxylate (sodium ethylenediaminetetraacetate) and the like may be contained. In addition, a solvent for the compound of the present invention, for example, a water-miscible organic solvent such as methanol, ethanol, propanol, isopropyl alcohol, n-butyl alcohol, dimethylformaldehyde, and dioxane can be contained.

In carrying out the complex salt diffusion transfer method, for example, British Patent Nos. 1,000,115 and 1,012,47
No. 6, No. 1,017,273, No. 1,042,477
As described in the above specification, it has been practiced to incorporate a developing agent into a silver halide emulsion layer and / or an image receiving layer or another water-permeable layer adjacent thereto. Therefore, in such a photosensitive material, a so-called “alkaline activating solution” containing no developing agent can be used as a processing solution for development. The processing liquid of the present invention is effective even with such a type of photosensitive material.

The silver halide emulsion of the lithographic printing plate used in the practice of the present invention can be silver chloride, silver bromide, silver chlorobromide, silver chloroiodide, or silver chlorobromoiodide. Is 50 mol% or more of silver halide. These silver halide emulsions include spectral sensitizers (spectral sensitizing dyes depending on the light source and application, such as camera type, laser light type, panchromatic type for color separation, etc.), gelatin hardener, coating aid, antifoggant , A plasticizer, a developing agent, a matting agent, and the like.

The binder used in the silver halide emulsion of the lithographic printing plate of the present invention is usually gelatin, and a part of gelatin is starch, albumin, sodium alginate, hydroxyethylcellulose (HEC),
Hydrophilic polymer bonds such as gum arabic, polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP), carboxymethyl cellulose (CMC), polyacrylamide, styrene-maleic anhydride copolymer, polyvinyl methyl ether-maleic anhydride copolymer One or two or more agents can be substituted. Further, an aqueous dispersion (latex) of a vinyl copolymer may be used.

Under the silver halide emulsion layer (on the side of the support), an undercoat layer for improving adhesion and / or an undercoat layer for the purpose of preventing halation may be included. This layer contains a developing agent and a matting agent. Can be included.

The support on which the silver halide emulsion is coated is
Paper, various films, plastics, paper coated with a resin-like substance, metal plate, and the like can be used.

The physical development nuclei used in the physical development nucleus layer include:
Such chemicals are well known and include antimony, cadmium, cobalt, palladium, nickel, silver, lead, zinc,
And their sulfides can be used. The physical development nucleus layer may also contain a developing agent or may contain a hydrophilic binder.

[0046]

EXAMPLES The present invention will be described below in more detail with reference to examples, but it is needless to say that the present invention is not limited thereto.

Example 1 A matted layer containing silica particles having an average particle size of 5 μm was provided on one side of a polyester film support subjected to an undercoating treatment, and an amount of carbon having an optical reflectance of 633 nm of 3% was provided on the opposite side. 20 including photographic gelatin, including black
An antihalation undercoat layer containing 7% by weight of silica powder having an average particle diameter of 7 μm (adjusted to pH 4.0), and a silica powder having an average particle diameter of 7 μm after chemical sensitization was added to 5% by weight of photographic gelatin. Sensitized silver chloride emulsion (adjusted to pH 4.0) which had been spectrally sensitized. The undercoat layer gelatin was 3.5 g / m ² , and the emulsion layer gelatin was 0.8 g / m ² .
The coating was performed at a rate of 1.0 g / m ² of silver halide in terms of m ² and silver nitrate. The undercoat layer and the emulsion layer contain formalin as a hardening agent in an amount of 5.0 mg / g based on gelatin. After heating at 40 ° C. for 14 days after drying, the plate No. 2 of JP-A-54-103104 Example 2 was placed on this emulsion layer. The nucleus liquid described in 31 is applied and dried to produce a lithographic printing plate. The silver halide emulsion was obtained by adding 4 × 10 ⁻⁶ mol of rhodium chloride per mol of silver halide at the time of physical ripening, and had an average grain size of 0.40 μm.
The thus obtained lithographic printing plate precursor is image-exposed with a plate making camera having an image reversing mechanism, developed with the following developer A (used solution) at 30 ° C. for 30 seconds, and subsequently with the following neutralizing solution Processed.

Developer A Sodium hydroxide 24 g Potassium hydroxide 8 g Anhydrous sodium sulfite 50 g 2-methyl-2-amino-1-propanol 30 g Uracil 0.2 g Add water to make 1 liter.

Neutralizing solution Ethylene glycol 5 g Colloidal silica (20% aqueous solution) 1 g Citric acid 10 g Sodium citrate 35 g Water is added to make 1 liter.

On the other hand, by comparing the developer A with the compound 3 of the present invention and an organic development inhibitor, the developer B-
H was prepared. However, the developer C used as a comparative example was a representative compound which is a mercapto group-containing inhibitor, as shown in the following formula. The development was carried out in exactly the same manner as the above-mentioned developer A. Then, the printing plate was set on an offset printing machine, the plate surface was sufficiently wetted with an etching solution having the following composition, and printing was performed using a moisturizing solution having the following composition.

Etch liquid Water 600 ml Isopropanol 400 ml Ethylene glycol 50 g

Humidification liquid Water 8 l Succinic acid 6 g Sodium sulfate 25 g Ethylene glycol 100 g Colloidal silica (20% aqueous solution) 28 g

The printing machine is AB Dick 350CD
(Trademark of offset printing machine manufactured by AB Dick) was used. 5,000 printing plates obtained with the developer A,
The printing plate obtained with the developing solution B had a partial loss of the transferred silver image by 10,000 sheets, whereas the printing plate obtained with the developing solutions D and E of the present invention had a thickness of 25%. 2,000 sheets, F ~
In the printing plate obtained in H, no loss of the transferred silver image occurred even on 50,000 sheets.

[0054]

[Table 1]

Table 1 shows the results obtained by combining Chemical formula 3 used in Example 1 with Organic inhibitor 23 having no mercapto group (addition amount: 0.19 g / l). Was. The printing durability was evaluated on the following four levels according to the number of prints when the printing was continued for 1,000 to 50,000 sheets, and the ink was removed from the silver image area. A 50,000 or more B 25,000 C 10,000 D 5,000

Example 2 Instead of the organic inhibitor 23 (addition amount: 0.19 g / l) and the compound 3 used in the developer D of Example 1, each of the compounds 4 to 22 was added in an amount of 0.5 g / l. The plate-making process was carried out in exactly the same manner as in developer A except that developer 1 to 19 were added. The printing results are shown in Tables 2 and 3. In all cases, the printing durability was better than that of developer A.

[0057]

[Table 2]

[0058]

[Table 3]

As is clear from Tables 2 and 3, the lithographic printing plate obtained by using the compound of formula 2 in combination with an organic development inhibitor containing no mercapto group has an image with remarkably excellent printing durability. Compared to lithographic printing plates obtained with silver and organic development inhibitors containing a mercapto group, the fine line portions of the manuscript are reproduced well, and long printing without mechanical abrasion due to the printing of the fine line portions Was tolerable.

The lithographic printing plate made with the developer according to the present invention can improve the loss of the transferred silver image, dramatically improve the printing durability, and do not lower the ink receiving ability.

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Claims (1)

(57) [Claims] In a lithographic printing plate developer utilizing a silver complex salt diffusion transfer method, at least one compound represented by the following formula and at least one organic development inhibitor containing no mercapto group and no thione group: And a developer for a lithographic printing plate. Embedded image In the formula, R represents an alkyl group, an aryl group , an aralkyl group, or a hydroxyalkyl group, X is a hetero atom of Se, S, O, N or a methylene group, an alkyl-substituted methylene group, and Z is a 5-membered ring or The remaining atoms required to form a 6-membered ring are shown.